As I work making Friendly-traceback provide more useful information regarding the cause of an exception, I sometimes encounter weird "corner cases" about either Python itself  or occasionally about pytest . Today, it was pytest's turn to give me a new puzzle to solve.
Consider the following:
If you run this, Python will give you a TypeError: 'float' object cannot be interpreted as an integer
Using Friendly-traceback's console , I get something slightly more informative.
Actually, I can get even more information using "explain()":
Time to add this new working case to the unit test suite. I create a barebone one for the purpose of this blog, without capturing the output and comparing with what is expected.
import friendly_traceback def test(): try: range(1.0) except: friendly_traceback.explain_traceback() if __name__ == '__main__': test()
Here's what happens if I run this using Python:
A new float variable, "start", has suddenly appeared, seemingly out of nowhere. Note that this pytest oddity is not revealed if we use a string instead of a float as the wrong type of argument.
Time to move on to handling other cases ...
 See this blogpost.
 An issue that I filed about a previous case seems to have disappeared and all that remains is this question on Stack Overflow.
 This is my local development version; the example shown here will be handled by versions 0.2.8 and later, to be released on pypi.